added: now we have a fourth part in permissions (guests)

e.g.: 07555 means:
           7 for owner
           5 for group
           5 for others
           5 for guests (not logged users)
added:     the sticky bit for directories
           e.g. permissions to a directory with a sticky bit set
           can be set to: 017555
rewritten: rm/mv winix functions to correctly understand the sticky bit
added:     Dir::FollowLink() recognizes ".." and "." now
           consequently System::FollowAllLinks recognizes it too
added:     umask -- calculating privileges for new files/directories
           all users have their own umask (in meta)
           and there is one in the config
           (for guests and when a user has not definied its own one)
removed:   mount option: only_root_remove



git-svn-id: svn://ttmath.org/publicrep/winix/trunk@801 e52654a7-88a9-db11-a3e9-0013d4bc506e

core/dircontainer.h

@@ -2,7 +2,7 @@
  * This file is a part of Winix
  * and is not publicly distributed
  * 
- * Copyright (c) 2008-2010, Tomasz Sowa
+ * Copyright (c) 2008-2012, Tomasz Sowa
  * All rights reserved.
  * 
  */
@@ -48,7 +48,7 @@ public:
 
 	bool DelById(long id);
 
-	ParentIterator ParentBegin();
+	ParentIterator ParentBegin(); // IMPROVE ME: may it should be renamed to ChildBegin() similarly as FindFirstChild() ?
 	ParentIterator ParentEnd();
 	ParentSizeType ParentSize();
 	bool           ParentEmpty();